It's fair to say we are not even a pin prick size in relation to the universe - to believe we are the only form of life in the Universe is naive & foolish. (Note: there are LIVING Bacteria' that do not need water or oxygen to survive)
I think it's also foolish to believe we are the most developed and have the most advanced technology in the universe.
Beings of a higher intelligence and technology (capable of travelling further than we can imagine due to our current technology) once visited and planted intelligence, technology and relics upon earth (Pyramids, Chichen Itza etc)
How would our ancient ancestors describe these 'beings' that flew around and came from the heavenly skies? - AS Gods, (Eziekels Chariot) Religious texts are full of references to the Gods coming from the skies.
When our space travel here on earth advances, we to will be the new 'Gods' to a distant planet and race - a new religion for them to worship.